Japanese researchers have made a breakthrough in cancer treatment by exploiting a chemical produced by cancer cells to create a powerful drug. The team, led by Katsunori Tanaka at the RIKEN Pioneering Research Institute, has developed a method to use carbon monoxide released by cancer cells to manufacture anticancer compounds directly inside the cells. The approach involves delivering a metal catalyst into cells and using the excess carbon monoxide in cancer cells to drive a chemical reaction that produces a toxic compound. This reaction occurs primarily in cancer cells, where enough carbon monoxide is available, while sparing normal cells. The team's strategy is to replace the direct delivery of toxic drugs with relatively harmless compounds that become active only after entering cancer cells. The researchers have successfully tested their system in laboratory experiments, demonstrating that it can selectively attack cancer cells without harming healthy cells. They have also shown that the toxic drug is not produced in the bloodstream, reducing the risk of damage to blood cells. The team's long-term goal is to replace traditional chemotherapy with a more targeted approach that uses substances already present inside tumors to generate therapeutic drugs exactly where they are needed. This innovative approach could potentially lead to safer and more effective cancer treatments. The researchers have already made significant progress in their experiments, with the system successfully producing the anticancer compound in cultured liver cancer cells. The next step is to test the approach in animal models, which could pave the way for clinical trials and potentially lead to a new class of cancer treatments. This breakthrough has the potential to revolutionize cancer treatment by providing a more targeted and effective approach. By exploiting the chemistry of tumors to produce drugs directly at the disease site, the researchers aim to limit damage to healthy tissue and reduce the harm associated with traditional chemotherapy.